Circuit and signaling apparatus for district telegraph and telephone systems



T. N. VAIL. Circuits and Signaling Apparatus for District Telegraph andTelephone Systems. No. 224,855. zgafemed Feb. 24, Isso.

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N'FETERS. PNUTOJJTHOGRPHER. WASHINGTON. D CA UNITED STATES PATENT(EETQEs THEoDonE n. vAiL, or' BOSTON, MASSACHUSETTS.`

"CIRCUIT AND SIGNALING APPARATUS FOR DISTRICT TELEGRAPH AND TELEPHONESYSTEMS.

SPEcIFIcA'rIoN forming part of Letters Patent No. 224,855, datedFebruary 24, 1880.

Application iled'August 20, 1879.

To all whom it may concern :Be itknown that I, THEoDoRE N. VA1LofBoston, in the county of Suffolk and State of Massachusetts, haveinvented a new and useful Improvement in Circuits and SignalingApparatus for District Telegraph and Telephone Systems, oi which thefollowing is a specification, reference being had to the accompanyingdrawings.

The object of this invention is to facilitate the sending of individualsignals to a series of communicating stations in a district-telephonesystcm; and to this end the invention consists in the combination, withtwo or more circuits passing through the several stations in the system,of apparatus at each station acting to cause the production of a signalby the i joint action of changes in the electrical condition of theseveral circuits, and of' an individual Signal at each station by adifferent combination of these changes for each of the several stationsin the circuits.

`It will be obvious to the electrician that this result can beaccomplished. in many different ways. When there are two main circuitsit can be accomplished by the use at each station of the doublepolarized relay invented by myself and George L. Anders, of Boston,Massachnsetts, for which -we have led an application for a patent of theUnited States.

In the accompanying drawings, Figure 1-is` a plan view of this relay.Fig. 2 is a side view of the same 5 and Fig. Sis a diagram showing themanner of using this double relay with two circuits passing through theseveral stations of a district-telephone system.

In these several gures the same letters rel fer to the same parts.

contact is made at the same time on each side of the relay by eachmagnet; but at each station thecontacts will be different, so that thecurrents which will cause the bell at any one station to ring will notclose the local circuit and cause the ringing oi' the bell at any of theother stations. This is shown in the diagram, in which it will be seenthat the local circuit through the signal-bell at station l is closed bymaking contact at the same time on point l with` the magnet A and onpoint a with the magnet A by currentsot1 one polarity, while thelocal'circuit through the signal-bell at station 2 is closed'at the sametime, making contact on point 4 with the magnet A and on point d withthe magnet A by currents of the other polarity.

It will thus be seen that with this arrangement, when a current of acertain polarity and of a certain strength is used with one of themagnets of the 'relay to make a contact on one side, four differentcontacts can be made on the other side by the other magnet by sendingcurrents of different polarity and of different strength, andconsequently by sending two currents in different combination from thecentral office sixteen stations on the line can each receive anindividual` signal.

A local circuit at each station may be dispensed with, and the currentfrom one circuit may be shunted through the signal-bell magnet when theproper connections are made.

The connections with the telephones are made in the usual manner, andtherefore are not shown.

I do not conline my invention to the use of two circuits, or to the useof the electrical conditions described; but

What I claim as my invention, and desire to secure by Letters Patent, is

l. In a district telegraph or telephone system, a series of stations ontwo or more circuits, in combination with an apparatus at each stationfor receiving calls from the central office operated on both or all thecircuits, in which apparatus, by a different combination for eachstation of changes in the electrical condition of the several circuits,an individual call for each station is produced, substantially as andfor the purpose Set forth.

IOO

larized tongues B B', springs C C', and their respective contacts', thesignaLbell and its circuit, and two parallel main circuits, one passingthrough one magnet and the other passing through the other magnet,substantially as and for the purpose set forth.

In Witness whereof I have hereunto signed this specification, inpresence of tWo subscribing Witnesses, on this 11th day of August, 1879.

THEODORE N. VAIL.

Witnesses:

GEO. L. BRADLEY, ALEX. L. HAYES.

